A routine security screening at upstate New York's Watertown International Airport (ART) took a startling turn when TSA officers discovered a spent smoke grenade hidden inside an aerosol container in a passenger's carry-on bag. The discovery was made by Transportation Security Administration (TSA) officers recently, according to a Sept. 24 release from the agency. During inspection, officers found the spent M18 smoke grenade.

SHARP WEAPON DISCOVERED BY TSA TUCKED INSIDE UNUSUAL ITEM IN PASSENGER'S CARRY-ON BAG In a statement, TSA Officer Yessenia Alvarez, who was operating the X-ray machine at the time, said she "didn’t like how the item appeared," referring to the unusual-looking aerosol container. "I called over Lead TSA Officer Melissa Graffam and told her I did not have a good feeling about it," said Alvarez. "I was very stunned when I saw the item on the screen."

The officer added that she had "seen these types of items in training scenarios." AIRPORT X-RAY REVEALS SHOCKING ILLEGAL STASH CONCEALED BESIDE PASSENGER'S XBOX Graffam said the item "looked funny" when she saw it on the X-ray screen. "I saw from the image that the top of the can didn’t look right but appeared to be empty," she said. "It was located in the side pocket of the bag, so I opened it and saw it was an M18 smoke grenade." Graffam said the discovery was particularly unusual for the small airport, where officers typically encounter prohibited items such as knives and oversized liquids. When she asked the passenger why the smoke grenade was in his bag, he told her he had forgotten it was there, according to the TSA. "I found [that] strange because his bag only had a few items in it," Graffam said.

Lead TSA Officer Debra Alcock, who was serving as acting supervisor, then notified the Syracuse TSA Coordination Center and a TSA explosives expert — who confirmed the grenade was not live. The smoke grenade ranked among the most memorable finds Alcock has seen during her time with the agency, the release said. CLICK HERE FOR MORE LIFESTYLE NEWS "The teamwork in resolving this issue was excellent," said Alcock. "Everyone did their part to help control the checkpoint while we resolved the situation." Brian Bushnell, TSA's federal security director for upstate New York's airports, said the incident serves as a reminder for travelers to check their bags before leaving home.

"Spent, inert or replica explosive items are not allowed through the checkpoint and can cause delays, disrupt operations and prompt a law enforcement response," said Bushnell. "When in doubt, travelers should leave the item at home or check TSA’s resources, such as TSA.gov, before packing." Though many people believe that spent grenades are not hazardous, officials warn that they can still pose risks. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has issued public safety alerts regarding vintage grenades in particular.

Recently, at Tampa International Airport, TSA officers discovered another alarming object. TSA Officer Andrew Carter was screening the passenger's carry-on bag with an X-ray machine when he noticed something unusual about the flashlight — and flagged the bag for a closer look. He ultimately found a 4-inch, double-edged knife concealed inside a baseball bat-shaped flashlight, according to an employee story published on the agency's website.

"Do not try to test the system," Keith Jeffries, the Florida-based vice president of K2 Security Screening Group and a former federal security director for TSA at Los Angeles International Airport, told Fox News Digital about the knife incident. "If you do, you will be caught." Kelly McGreal of Fox News Digital contributed reporting.